


It's You

by ahegaotyun



Category: TOMORROW X TOGETHER | TXT (Korea Band)
Genre: A/B/O, Alpha Choi Yeonjun, Alpha/Beta/Omega Dynamics, Biting, Bottom Huening Kai, Fluff, Fluff and Smut, Knotting, M/M, Marking, Mates, Mating, Mating Cycles/In Heat, Omega Huening Kai, Royalty, Smut, Top Choi Yeonjun, alpha yeonjun, omega Kai
Language: English
Status: Completed
Published: 2020-12-25
Updated: 2020-12-25
Packaged: 2021-03-10 17:14:51
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,750
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28300710
Author URL: https://archiveofourown.org/users/ahegaotyun/pseuds/ahegaotyun
Summary: In a world where people find their true mates by being driven almost out of their minds with need when the younger of the pair turns eighteen, Prince Choi Yeonjun has been waiting almost three years - since he turned eighteen - for his mate to catch up.On the fourteenth of August, almost three years after his eighteenth birthday, Prince Choi Yeonjun wakes up burning.
Relationships: Choi Yeonjun/Huening Kai
Comments: 4
Kudos: 164
Collections: moa secret santa 2020





	It's You

**Author's Note:**

> hello,,,,
> 
> god im nervous i really hope my secret santa likes this. i was told to write yeonkai, a/b/o, fluff and smut and im pretty sure this qualifies so ?? here u go
> 
> merry christmas !!

On the fourteenth of August, almost three years after his eighteenth birthday, Prince Choi Yeonjun wakes up burning.

Or – a more accurate word would be _simmering_ : the heat flows beneath his skin, rushing through his veins as if it had always been there: a volcano on the verge of erupting. He’s sweating, breath short, and he sits up so quickly he has to blink away dark spots from his vision. Pushing his damp fringe back, his eyes dart about his room, taking in the lavish furniture; the expensive curtains; the chandelier: things that had always been there. Nothing is different. His room in the castle is as it always has been.

Except –

The door opens and that thing – that _smell_ – the thing that Yeonjun identifies as being the cause of his burning drifts through; just a tendril of it, faint but recognisable, and Yeonjun’s head snaps up immediately. He barely notices his manservant walking in; greeting him; opening the curtains – he barely notices anything until there’s a hand on his arm and he’s snapping: turning and growling at whoever had dared to stop him, eyes glowing red.

“Woah! Woah, woah woah, calm down, it’s just me! It’s just me,” Soobin says, eyes wide, and Yeonjun blinks, breathing hard. He realises that he’s now standing, halfway to the door, hand already outstretched, ready to turn the handle so that he can leave his room and go to find –

Find what?

“I … sorry, I don’t …” Yeonjun mutters, eyebrows furrowed. The heat is increasing and it’s making it impossible to think: as soon as the beginning of a coherent thought forms in his mind, it’s gone, replaced by need … need to find … find what …?

“Sire, are you … is it time? I can alert somebody and have them gather all omegas who turned eighteen today – ”

“Omega.” Yeonjun interrupts. That’s it, that’s what he needs to find – that’s the answer to this raging heat beneath his skin – he needs his omega –

“Okay, alright, no problem, I can – woah, woah, wait a second, I don’t think it’s a good idea for you to – sire – _Yeonjun_ – ”

Yeonjun runs.

Soobin’s panicked voice fades behind him, and Yeonjun doesn’t even register when he informs the guards of Yeonjun’s condition in a rushed tone and footsteps begin to thunder behind him, voices echoing on the castle walls – “your Highness – your Highness, stop - !” –

The smell increases in potency with every step Yeonjun takes, and it makes his veins burn hotter; faster; if he could think coherently, he would realise that he is still wearing his nightclothes, barefoot, hair a mess, but as it is he simply runs, barely hearing the startled voices of the servants he passes. The footsteps behind him begin to fade, and Yeonjun rounds a corner, a growl brewing in his throat; the smell is so close he can almost taste it; there are shouts from behind him and a guard stationed a few feet ahead of him turns, registering his presence –

Then, rage is all Yeonjun knows as hands clamp around his arms; chest, waist – he roars, struggling against the guards, the only thing in his mind the thought of _omega omega find omega claim my omega my omega find my omega mine_

Two people emerge from a large set of ornate doors to Yeonjun’s left – the doors to the throne room – and walk towards them. Yeonjun bares his teeth, snarling, fire glowing hot –

“Choi Yeonjun, you do not _growl_ at me, boy.”

The fire dies down – slightly.

Yeonjun blinks, vision clearing of red enough to realise that the people in front of him are his parents, and his mother’s glare is piercing him, challenging him – Yeonjun holds her gaze for a tense few seconds, before dropping it with a slight whimper, unable to assert dominance over an older, more powerful alpha of such high status: the queen.

She sighs.

“Goodness me, what a morning. Not only has my son gone positively feral over his mate finally presenting, but some crazed omega has broken into the castle. Oh, not _your_ omega, my dear, just a silly little stable boy,” Yeonjun’s mother adds, with some disdain, when Yeonjun’s eyes widen and he jerks forward against the arms restraining him at the mention of an omega. After regarding him for a long few seconds more, in which time Yeonjun feels fire crackling almost unbearably deep in his stomach, the queen sighs once more, and turns, walking briskly towards the throne room. Guards on either side of the huge doors step forwards to open them, and she, along with her husband, sweep through, head held high.

“Come, bring him in,” she says loudly, tone filled with authority, and the guards holding Yeonjun scramble to obey, hauling the alpha through the doorway. “We will have to start the search immediately. If he’s this bad now, the omega must be near, so we won’t have to look far. I need every single person within a mile of the castle who turned eighteen today, and presented as an omega, to be brought to the castle straight awa – ”

The doors, which had closed behind Yeonjun and the guards, fly open with a bang, and, suddenly, Yeonjun is ablaze.

The smell – the one that woke him; the one that caused the fire that is currently engulfing Yeonjun whole – is suddenly everywhere, clinging to Yeonjun’s skin and flowing into him, uninhibited; he gasps, almost buckling beneath its weight; then, he’s shaking his head – _get a hold of yourself_ – and turning, the guards’ grip having become lax due to shock –

There is a boy, standing there, in the doorway. Yeonjun takes him in, vision suddenly in slow motion, as the guards on either side of the door rush towards him in half speed. He’s sweating, like Yeonjun; shaking, gasping – his eyes are wide and desperate, glazed with unshed tears, and they meet Yeonjun’s immediately, as if they had been looking for him all along. His lips move.

_Alpha,_ he mouths, as his knees buckle.

Yeonjun runs.

Somehow, he reaches the omega, his omega, before the guards, and then his arms are wrapped around the boy’s waist, and he’s holding him close, so close – the guards still draw closer and he growls, eyes undoubtedly red; they halt, gazes darting to somewhere behind him as if searching for instructions, and whatever they see makes them back away. Yeonjun’s chest rumbles in satisfaction. _Yes_ , he thinks, _stay back. He’s mine_.

“Mine,” he repeats, this time out loud, spoken into his omega’s neck, and the boy in his arms trembles, gasping out a weak “ _alpha_ …” as his knees buckle fully and he lets himself be held entirely by Yeonjun. Yeonjun holds him up easily. He wouldn’t dream of dropping his omega.

“My omega,” Yeonjun growls, and hot breath hits his neck as the boy sighs shakily, nuzzling into the skin.

“My … alpha …” He responds weakly, clearly drained, and Yeonjun holds him tighter. Unable to form full sentences due to the overwhelming smell of his omega, his mate, surrounding him, Yeonjun grits out a short “name?” into the boy’s neck, repeating it when he doesn’t seem to register the question. He gets a small “Kai,” for his trouble, and repeats the name over and over in his head; it fills him up from the inside out. It’s all he can think about.

_Kai_. Omega. My omega. My mate.

Yeonjun leans down, and bites.

Yeonjun barely remembers the scandalised gasps and the outraged yelp from his mother. In the moment, he only heard them as if from underwater: they were muffled; far away; unimportant. All he remembers is the way his omega – _Kai_ – had shuddered, whimpering weakly – a stark contrast to the way his grip tightened on the back of Yeonjun’s shirt. For a moment, Yeonjun was still, revelling in the feeling of mating his omega, _finally_ , after almost three years of waiting. He allowed himself to simply exist in the sweet scent of his mate: his mate who had run to him, in heat and desperate; his mate who had sought him out, and only him. Because he needed him.

“I’ll look after you, my omega,” Yeonjun had muttered lowly into Kai’s neck. “You don’t have to hurt anymore. I’ll make it better, I’ll make sure you’re safe.”

And with that, he had scooped the omega up into his arms and left.

Words followed him: _how could this – just a stable boy – not supposed to – well, nothing we can do – surely this can’t –_

But now, his omega is in his arms, and he could not care less.

Now, his omega is on his lap, squirming in his arms as he pants against his neck, arms clinging desperately onto his shoulders as he whimpers –

“Alpha, it _hurts_ – ”

“I know, baby, I know, I’ll make it better – ”

Without thinking, Yeonjun rolls them over and Kai’s back hits the mattress, Yeonjun’s body pressing him down; covering him entirely. Kai whines, head lolling backwards, neck presented unhesitatingly to his alpha. He’s naked already, having had his clothes ripped off as soon as the door shut behind them by a feverish Yeonjun, and Yeonjun himself is the same, bare skin rubbing against the omega. He feels a satisfied growl rumble deep in his chest at the way Kai’s legs fall open, letting him settle between them, and he takes advantage immediately, pushing his hips forwards and revelling in the gasp; the jerk of Kai’s body as he does.

“I’ve waited – ” Yeonjun breathes, leaning down to take a deep breath of where Kai’s scent is most potent: his neck. “I’ve waited for so long – god, finally, my omega, I get to have you – ”

“I’m sorry,” Kai whispers, eyes shut tight, and Yeonjun jerks upwards, feeling the inexplicable urge to whine at the spike of sadness in Kai’s scent. He brings one hand up to cradle his face, silently urging him to open his eyes.

“Why – why are you apologising, love? There’s nothing to apologise for, you’re perfect,” Yeonjun says in a rush, feeling his cheeks heat a little at the intense words. Finally, Kai’s eyes flutter open, as his red scatters across his face, too.

“I … I kept you waiting …” Kai mumbles, staring up at Yeonjun with wide, nervous eyes, as if worried that Yeonjun might be angry with him for taking so long to turn eighteen. A disbelieving, breathy laugh escapes Yeonjun’s mouth and he can’t stop himself from cooing at his sweet omega, leaning down to press a soft kiss onto the tip of his nose. He opens his mouth to respond; to reassure Kai that he isn’t angry; it isn’t his fault – but Kai continues before he can.

“And – and I’m not – I’m not somebody important, like you. I – my parents are labourers. I work at the stables, with the horses – I’m not of noble blood, I’m not royalty, how could I ever be worthy –” He cuts himself off with a pained whimper, hand flying to his stomach, clearly feeling the effects of his presentation-triggered heat, and Yeonjun feels the urge to protect him so strongly that he thinks if anybody entered the room at this very moment he might tear himself in half with the need to stay with him, as close as possible, whilst also ripping the head off the intruder.

“Darling – my love, my omega, my mate,” Yeonjun begins, holding Kai’s face in both his hands. “You are worthy, no matter your status. You are my mate. You are my omega, and I am your alpha. Nothing else matters.”

Yeonjun feels hands cling onto his wrists – then, his shoulders; his back – as if they can’t decide where to hold onto, so they try to grasp everything. The omega below him swallows hard, eyes wide and undoubtedly devoted; loving, as they stare up at Yeonjun. They glisten slightly with tears, and that’s all it takes for Yeonjun to lean down and press his lips to his mate’s, initiating their first kiss.

Kai’s lips tremble beneath his; his breathing is shaky as he opens his mouth readily; desperately, as if all he wants is to let Yeonjun in; to let Yeonjun have him in every way. And Yeonjun takes that as the invitation that it is and presses down with a growl, working his lips over Kai’s, acting on pure instinct. It’s clumsy, of course – neither of them have experience – but it’s perfect, because it’s them, and they’re made for each other.

“ _Alpha, take me_ ,” Kai gasps, breaking away from the kiss suddenly as if unable to hold the words in anymore, and then the fire is back all at once, licking at Yeonjun’s skin as if it had never left – and maybe it hadn’t, and he had simply been distracted by the panting omega below him. Breathing hard, Yeonjun grinds down once, unable to stop himself – Kai jerks, moaning, nails digging into Yeonjun’s back – before reaching down and hitching Kai’s left leg over his arm, opening the omega up to him. With the other hand, he smooths over the skin of Kai’s right thigh, groaning lowly at the way it gives when he squeezes; at the way Kai makes a small, desperate noise and covers his face with his hands, flustered at the attention he’s being given. Endeared, Yeonjun smiles slightly, but then his attention is back on Kai’s lower half, and he reaches the place his omega needs to be touched the most.

“Ah – alpha –”

“You’re so wet, lovely,” Yeonjun says, not paying attention to the words coming out of his mouth as Kai whines, noises still muffled by his hands. “I’m sorry, I’ve made you wait for too long. I’ll make you feel good, love, I promise. I’ll take care of you.”

With that, he pushes in a finger, almost awed at the way it slides in so easily – so easily he’s able to replace it with two almost immediately. And, oh, Kai is almost incoherent already, Yeonjun takes great satisfaction in noting – he’s whimpering, body jerking as his thighs twitch as if trying to close, stopped by Yeonjun’s hand every time – _need you nice and open for me, love_ –

“ _More_ , alpha, _please_ ,” Kai wails, and Yeonjun feel his dick throb at the way his omega is being so unashamedly desperate for him.

“Of course, anything you want, my pretty omega,” Yeonjun murmurs, and pushes in three fingers, moving them in and out when Kai arches and moans, hands finally leaving his face in favour of gripping onto the pillowcase on either side of his head. He’s beautiful: cheeks rosy red, glossy lips parted, eyes shining with tears of pleasure, and all Yeonjun can think about is how lucky he is to have him as his mate. He speeds up his pace, thrusting his fingers into Kai’s hole hard, and Kai shouts, dick jerking and drooling on his stomach.

“Ah – _alpha_ – ngh, oh, alpha, _stop, I wanna come on your cock_ –”

“ _Fuck_ ,” Yeonjun growls, pulling his fingers out immediately and hitching Kai’s other leg over his as he shuffles forwards on his knees. His eyes dart between Kai’s dazed expression and where he’s positioning his cock at the omega’s hole, searching for any hint of discomfort on the younger’s face. He finds only want.

“I’m gonna fuck you now,” Yeonjun breathes and Kai nods immediately, a fast, desperate movement, eyes pleading. “Gonna make you feel good, my beautiful omega.”

He pushes in, watching as Kai’s eyes screw shut and his mouth falls open in a thin, breathy moan. Yeonjun lets out a shaky breath, chest heaving as he adjusts to the feeling of Kai all around him, letting him in so readily. His hips meet Kai’s and the noise Kai lets out is small; vulnerable, and Yeonjun is there immediately, leaning over him; kissing over his face and murmuring words of reassurance and praise.

“Are you alright, love? You feel so amazing, my omega, so good – you’re so beautiful, so, so beautiful, my lovely omega, I’m so lucky to have you – so lucky such a pretty omega let me have him –”

Kai shakes his head, eyes still shut tightly, and Yeonjun pushes up slightly, poised to pull out if Kai says the word –

“I’m the lucky one,” Kai whispers, eyes opening, wide and imploring, “to have you as my alpha.”

For a moment, they simply stare at each other, heavy breaths mingling as they revel in each other’s closeness. Then, Kai speaks.

“Now, fuck me, _alpha_.”

As if Yeonjun could say no to that.

He pulls out and snaps his hips forwards, watching Kai’s eyes widen as a small moan is pushed from his lips. His hands move to grip onto Yeonjun’s back, nails digging in as Yeonjun fucks into him again; then, again, and again, until Kai is moaning, head thrown back as he’s pushed up the bed with every thrust. His neck stretches, long and lean, in front of Yeonjun’s eyes, and he is helpless to his urges when his very own mating mark is staring up at him proudly at the base of the otherwise spotless stretch of skin.

“Gotta mark you, gotta let them know you’re mine,” he mutters feverishly before diving into Kai’s neck and beginning to suck on a spot just above the mating mark. Kai’s reaction does not disappoint – the leg that isn’t still held up by Yeonjun’s arm clenches around his waist, and he moans loudly in Yeonjun’s ear, body arching up into him as his nails drag up his back to his shoulders.

“Please – yes – alpha – oh, mark me –”

Yeonjun speeds up, spurred on by Kai’s pleading words, making the omega moan louder, voice echoing off the high ceiling and stone walls. He’s sure that if there is anyone outside the room, they can hear exactly what is happening inside, and the though makes satisfaction settle, hot and thick, deep in Yeonjun’s stomach. Let them know, he thinks, while sucking yet another mark into Kai’s neck. Let them know how well I take care of my omega.

Leaning back, Yeonjun takes in his work. Kai’s neck is covered in marks, but the mating bite still stands out, starkly pronounced at the base of the omega’s neck. As if realising he’s being surveyed, despite his eyes having fluttered shut with pleasure, one of Kai’s hands once again reaches up to feebly cover his face, and he lets out an embarrassed whine. However, his body contradicts him; he cranes his neck back further even as red creeps over his nose; his legs spread wider even as his hand covers his face. The sight of him, body being jerked up the bed with every thrust, is, to Yeonjun, pure art, and he lets his left leg fall from his arm’s grip in favour of leaning his arm on the pillow next to Kai’s head, needing to be closer to him.

“You’re perfect,” Yeonjun breathes, and Kai opens his eyes just enough to have Yeonjun trapped, awestruck in his gaze – effortless. Kai’s mouth opens as if to speak, but all that comes out is a needy whine of _alpha_ and Yeonjun groans, grinding his cock deeper into Kai’s hole, watching the way his mate’s face contorts with pleasure. Kai writhes beneath him, head turning one way and then the other, as if he doesn’t know what to do with himself, so overwhelmed with pleasure. It draws Yeonjun’s eyes back to his neck, once pure skin now littered with marks, and Yeonjun can’t help placing a hand over the length of it.

“Oh – alpha –” Kai’s eyes snap open, wide and desperate, and he’s gasping, throat bobbing beneath Yeonjun’s hand as he swallows. Oh, Yeonjun thinks, and squeezes, just slightly, hand wrapped firmly around Kai’s throat – and that’s it. The omega’s eyes roll back, and his mouth drops open fully; his legs draw up and he’s coming, body jerking as he gasps and gasps and whines and gasps, nails undoubtedly leaving marks across Yeonjun’s back.

“ _Fuck,_ you’re beautiful,” Yeonjun moans as Kai clenches hard around his cock.

“Can’t – h – _ah_ – can’t stop – coming – _ah_ – _alpha_ –”

Kai is still jerking, eyelids fluttering as drool wets his bottom lip, and Yeonjun looks down to see his cock twitching weakly, white still leaking from its tip.

“Oh my – fuck –” Yeonjun groans, thrusting hard once more – Kai squeaks and holds on impossibly tighter – before burying himself deep inside his omega, feeling his knot swell as he grinds into Kai’s hole, letting out deep _ah_ s into Kai’s neck, breathing in his mate’s scent.

Afterwards, Kai is completely boneless – that is, until Yeonjun attempts to get up, after his knot has gone down, to find something to clean them up with – then, he cling on with both his arms and his legs, refusing to let the older go. It takes a solid fifteen minutes of coaxing before Yeonjun is allowed to get up, leaving a still dazed, pouting omega in bed. He returns from the bathroom in a rush after hearing a lost-sounding whimper, and sees Kai sitting up in bed, hair a complete mess, eyes wide and betrayed.

“You left,” He accuses, blinking hard. Yeonjun laughs a little, fondly, as he cleans them both, one hand wiping them down and the other clasped firmly in Kai’s.

“I had to go and find something to clean us up with, remember?” He says gently, thumb stroking over the back of Kai’s hand. Kai looks like he isn’t too happy with Yeonjun’s answer, but his only response is to flop back onto the bed so suddenly that Yeonjun is pulled along with a yelp, only just stopping himself from completely crushing the younger. He huffs out a fond, exasperated laugh at Kai’s smug expression, and falls to the side, gently turning Kai over so that he can press himself along the line of his back and snake an arm around his waist, pulling him close. He buries his nose in Kai’s neck and inhales, completely, entirely content.

When Kai’s heat is over, Yeonjun will have to deal with the repercussions of what they have done: the curses from his mother; the odd looks from the castle staff; the complications of a prince mating with a stable boy. He will have to deal with the potential awkwardness of interacting with Kai when they are both of clear mind, unaffected by pheromones.

But that is later, and this is now.

Now, he enjoys Kai’s contended little noise as he pulls the blanket over them both and settles down to sleep, somehow knowing that everything will be okay.


End file.
